Smokeless gas flare with specific gravity gas analyzer for reducing noise

ABSTRACT

A method and at least one gas flare for carrying out or practicing the method are disclosed for smokeless burning of undesired gas. Combined with a steam aspirating gas flare having a steam flow controller responsive to a gas flow detector to provide a combustible material is a specific gravity analyzer for controlling the steam flow controller further in relation to the specific gravity of the gas to be burned for providing a smokeless air-to-gas burning mixture in the flare with less steam usage and reduced noise.

United States Patent 1 Stranahan et-al.

[ Nov. 13, 1973 SMOKELESS GAS FLARE WITH SPECIFIC GRAVITY GAS ANALYZERFOR REDUCING NOISE Inventors: John J. Stranahan, Port Arthur;

John C. L. Hollier, Nederland, both of Tex.

Assignee: Texaco, Inc., New York, N.Y.

Filed:

Appl. No.: 266,794

June 27, 1972 US. Cl 43l/4, 431/90, 431/202,

Int. Cl.

Field of Search References Cited UNITED STATES PATENTS Webster et al431/90 l/l957 Zink et al. 431/90 9/1956 Verner et al 431/4 X PrimaryExaminer-William F. ODea Assistant Examiner-William C. AndersonAtt0rneyThomas H. Whaley et a1.

[ ABSTRACT 20 Claims, 1 Drawing Figure I i 1 y l 33 I l 1 T w 1 l l 1 11 1 i l l l STEAM FLOW 1 CONTROLLER SYSTEM l l 17 i ,V L

RAT/0 l J l STAT/0N i l 5.61 ANALYZER PAIENIEB m 1 3 191a STEAM FLOWCONTROLLER SYSTEM 6 2 (7- 7 n R a G Y .L 2 SA N A 8 9 Z N Om T AA ySMOKELESS GAS FLARE WITH SPECIFIC GRAVITY GAS ANALYZER FOR REDUCINGNOISE BACKGROUND OF THE INVENTION The government requires the burning ofall excess gases being admitted to the atmosphere. The collection ofthese gases is normally put into a flare line which is equipped with apilot light to ensure the burning of all gases.

Recent regulations require that this burning be smokeless in order toreduce air pollution and to be quieter to reduce noise pollution.

In order to keep a flare smokeless, as a steam aspirating gas flare forexample, the relative amount of steam used to draw in air for mixingwith the gas must be increased greatly as the average molecular weightof the hydrocarbon increases. Accordingly in operation, it has beennecessary to set the. steam-to-gas ratio high in order to maintain theflare smokeless when the highest molecular weight gas is being suppliedto the flare. Thus when a low molecular weight material, such as lowpurity hydrogen is going to the flare, the flare is noisy due to theroar of the steam jet in the aspirating flare nozzle. It often canbe'heard from 2 to miles away.

OBJECTS OF THE INVENTION Accordingly, aprimary object of this inventionis to provide a method for burning unwanted hydrocarbons in a steamaspirating flare smokelessly, with less steam wastage, and with reducednoise levels. I

A further object of this invention is to provide a method forcontrolling a steam aspirating gas flare for maintaining the flaresmokeless with less steam usage and with reduced noise for all gases,from the lightest to the heaviest molecular weight gases.

A still further object of this invention is to provide a method forsmokelessburning of undesired gas with reduced noise to vary the amountof air in the air-to-gas mixture relative to'the specific gravity of thegas to be burned.

Another primary object of this invention is to provide a gas flare forcarrying out or practicing the method of the invention for burningundesired gas.

Still another object of this'invention is toprovide a steam aspiratinggas flare that varies the amount of steam to the flare nozzle relativeto the specific gravity of the gas to be burned for providing asmokeless air-togas burning mixture in the flare with less steam usageand reduced noise.

A further object of this invention is to provide a steam aspirating gasflare that has a steam flow controller responsive to a specific gravityanalyzer for providing a smokeless flare utilizing the least steampossible for reducing noise.

Another object of this invention is to provide a gas flare forefficiently and smokelessly burning undesired gas having a wide range ofmolecular weight with less steam usage and reduced noise.

Still another object of this invention is to provide a smokeless flarethat is easy to operate, is of simple configuration, and is economicalto form and assemble.

Other objects and various advantages of the disclosed method andsmokeless flare for carrying out the method will be apparent from thefollowing detailed description together with the accompanying drawing,

submitted for purposes of illustration only, and not intended to definethe scope of the invention, reference being had for that purpose to thesubjoined claims.

The drawing diagrammatically illustratesby way of example, not by way oflimitation, a smokeless flare.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a schematic diagram of asteam aspirating gas flare utilizing a specific gravity analyzer forforming an efficient smokeless flare with parts in section.

METHOD OF MAINTAINING A GAS FLARE SMOKELESS WITH REDUCED NOISE Thisinvention comprises a method for maintaining a gas flare smokeless, andparticularly with reduced noise when utilizing an aspirating steamnozzle and when the molecular weight of the hydrocarbon varies.Accordingly, in operation it is necessary to adjust the steam-togasratio high to keep the flare smokeless when the highest molecular weightgas is going to the flame. Then when a lower molecular weight gas, suchas low purity hydrogen is being supplied to the flare, it is very noisy.A method for reducing this noise in a steam aspirating flare comprisesthe steps:

a. determining the specific gravity of the gas being burned, and

b. varying the amount of steam to the flare relatively to the specificgravity of the gas to be burned for providing a smokeless air-to-gasburning mixture in the flare with less steam usage and reduced noise.

In greater detail the method comprises the additional steps:

c. determining the amount of steam required to maintain a desiredsteam-to-gas ratio for the flare gas flow, and

d. multiplying the amount of steam supplied by a factor relative to thespecific gravity of the gas to be burnedto provide a smokelessair-to-gas burning mixture in the flare with less noise.

The last step above may be recited in greater detail as the step: L

e. varying the amount of steam in the steam-to-gas ratio in proportionto the specific gravity of the gas for providing a smokeless air-to-gasburning mixture in the flare with less steam and reduced noise.

In a high pressure gas aspirating flare the method comprises the steps:

a. determining the specific gravity of the gas to be burned, and I b.varying the amount of high pressure aspirating gas to the flare relativeto the specific gravity of the gas to be burned for providing asmokeless air-to-gas burning mixture in the flare with less highpressure gas usage andreduced noise.

DESCRIPTION OF THE PREFERRED EMBODIMENT .The invention disclosed herein,the scope of which being defined in the appended claims is not limitedin its application to details of construction and arrangement of partsshown and described, since the invention is capable of other embodimentsand of being practiced or carried out in various other ways, Also it isto be understood that the phraseology or terminology employed herein isfor the purpose of description and not of limitation. 1

The FIGURE discloses at least one steam aspirating gas flare 10, a flarecontrol system 11, and a specific gravity analyzer 12 designed forcarrying out or practicing the method of maintaining a smokeless flamein the flare with less steam usage and reduced noise. The flare controlsystem 11 may be a conventional system or like one disclosed inassignees Pat. application Ser. No. 192,453, filed Oct. 26, 1971,entitled Smokeless Gas Flare which comprises two portions, one portionfor very low gas flow rates in which the rate is too low for accuratemeasuring and a second portion for all other varying flow rates. Thepresent invention comprises also an article for carrying out orpracticing the method in the form of a specific gravity analyzercombined with a steam and gas control system to form the new andsuperior gas flare.

IMPROVED GAS FLARE SYSTEM The flare 10 comprises a conventional steamaspirating gas flare in which steam, or any other gas, is blown throughan aspirating nozzle to pull in air for mixing with the unwanted gas tobe burned in the atmosphere. A preferred gas flare is disclosed inassignees abovementioned patent application wherein the steam iscontrolled through a steam control system for the various flow rates ofgas flow to provide the proper steam-togas ratio for each gas flow ratefor accordingly producing the correct air-to-gas mixture in the flareburner to ensure a smokeless flame.

The new flare control system 1 1 comprises three flow rate detectors andtransmitters 13, 14, and 15 which are conventional or like thosedisclosed in assignees above-identified patent application for detectingthe flow rate of the gas in the main line 16. Previously, this flow rateinformation was transmitted straight to the steam flow controllers inthe steam control system 17 for varying the steam in proportion to thegas flow rate for supplying to the flare for providing a smokelessairto-gas burning mixture therein. Steam control system 17 isconventional or as disclosed in assignees aboveidentified patentapplication.

A conventional specific gravity analyzer 12, such as but not limited tothe Ranarexby Pfaudler Inc., New York, N.Y., has a specificgravity gassample conditioner portion 18 having a continuous circulating systemincluding an input-line 19 from the gas main line between the flow ratedetectors 13 15 and the flare 10, compressor 20, filter 21, andcoalescer 22, all for compressing and drying the gas. A back-pressureregulator 23 is on return line 24 to the gas main line 16. A gasslip-stream in line 25 is bled off the circulating system to a gasreducing valve 26, and a rotor-meter 27 for introducing the same volumeof pressurized gas as air to the conventional specific gravity analyzer12. A ratio station 28 for multiplying the specific gravity output of3-15 psi (pounds per square inch') for example by a factor between 0.7and 1.7 is connected between the specific gravity analyzer l2 and a highpressure select relay 29, the latter. relay choosing the larger signalbetween the gas ratio station output signal and a3 psi air pressureoutput from air reducing valve 30 for providing a further multiplyingfactor to control three variable ratio controllers, such as but notlimited to, pneumatic set ratios 31, 32, and 33. While only threepneumatic set ratios are shown, any number may be utilized, depending onthe number of flow transmitters required for the particular design ofthe steam control system.

With the latter ratios connected between the gas flow detectors 13-15and the steam flow controller system 17, the pneumatic set ratios 31-33multiply the output signals from the respective flow detectors by afactor relative to the specific gravity of the gas to be burned asrelayed through high pressure select ratio 29 and ratio station 28 fromthe specific gravity analyzer l2.

()PERATION In the disclosedsmokeless steam aspirating gas flare wherethe steam is supplied to the aspirating flare nozzle in proportion tothe gas flow, this steam flow is further controlled in proporation tothe specific gravity of the gas to be burned.

In greater detail, as the gas to be burned flows through the gas mainline to the flare, a continuous conditioning ofa gas sample is performedby portion 18 of the specific gravity analyzer before being processedthrough the specific gravity analyzer main portion 12. A signalproportioned to the specific gravity of the gas is transmitted to thepneumatic ratios 31-33 via ratio station 28 and high pressure selectrelay 29 for conditioning andamplifying the output signal from thespecific gravity analyzer 12. Here the steam control signals form thegas flow detectors 13-15 which are proportional to the gas flow in themain line 16 are modified further in proportion to the specific gravityof the hydrocarbon or gas to be burned for controlling the steam flowcontrollers in the steam flow control system 17 for decreasing the steamflow or steam-to-gas ratio for light hydrocarbons, for example, forensuring a smokeless air-to-gas burning mixture in the flare 10 withless steam used'and accordingly reduced noise.

Thus a method and at least one mechanism for carrying out or practicingthe method is disclosed for smokeless burning of undesired gas in asteam aspirating flare with less steam usage and reduced noise in amanner which meets each of the objects set forth above.

While a method and a smokeless gas flare with less steam usage andreduced noise for carrying out the method of the invention have beendisclosed in the accompanying-specification and drawing, it will beeviinvention, and it is accordingly desired to comprehend within thepurview of this invention such methods and modifications as may beconsidered to fall within the scope of the appended claims.

We claim: 1. A method for smokelessly burning gas with less noise in asteam aspirating flare having means for controlling the amount of steamto the flare for controlling the amount of air drawn in for mixing withthe gas for burning, comprising the steps of,

a. determining the specific gravity of the gas being burned, and I I 5 li b. varying the amount of steam to the flare relative to the specificgravity of the gas to be burned for providing a smokeless air-to-gasburning mixture in the flare with less steam usage and reduced noise.

2. A method as recited in claim 1 including the additional steps of,

a. varying the amount of steam relative to the amount of gasflowing tothe flare, and

b. varying the first amount of steam to a second amount of steamrelative to the specific gravity of the gas to be burned for providing asmokeless airto-gas burning mixture in the flare with less steam usageand reduced noise.

3. A method as recited in claim 1 wherein the second step comprisesfurther,

a. determining the amount of steam required to maintain a desiredsteam-to-gas ratio for the flare for the particular amount of gas flow,and

b. multiplying the amount of steam supplied by a factor relative to thespecific gravity of the gas for providing the smokeless air-to-gasburning mixture in the flare with less noise.

4. A method as recited in claim 1 wherein the second step comprisesfurther, v

a. determining the amount of steam required to maintain a desiredsteam-to-gas ratio for the flare gas flow, and

b. varying the steam-to-gas ratio relatively to the specific gravity ofthe gas for providing a smokeless air-to-gas burning mixture in theflare with less noise.

5. A method for smokelessly burning gas with less noise in a highpressure gas aspirating flare having means for controlling the amount ofhigh pressure gas to the aspirating flare for controlling the amount ofair drawn in for mixing with the gas to be burned, comprising the stepsof,

at. determining the specific gravity of' the gas to be burned, and

b. varying the amount of high pressure aspirating gas to the flarerelative to the specific gravity of the gas to be burned for providing asmokeless air-to-gas burning mixture in the flare with less highpressure gas usage and reduced noise.

6. A method for smokelessly burning gas with less noise in a steamaspirating flare'having means for controlling the steam-to-gas ratio inthe flare comprising the steps of, r g

a. determining a first steam-to-gas ratio relative to the amount of gasflow to the flare,

b. determining the specific gravity of the gas to be burned, and

c. varying the first steam-to-gas ratio relative to the specific gravityof the gas to provide'a smokeless air-to-gas burning mixture in theflare with less steam usage and reduced noise.

7. A method as recited in claim 6 wherein the last step comprisesfurther,

a. varying the amount of steam in the steam-to-gas ratio in relation tothe specific gravity of the gas to be burned.

8. A method as recited in claim 6 wherein the last step comprisesfurther,

a. varying the amount of steam in the stear'n-to-gas ratio in proportionto the specific gravity of the gas to be burned.

9. A method as recited in claim 6 wherein the last step comprisesfurther,

a. varying the amount of steam in the steam-to-gas ratio insubstantially direct proportion to the specific gravity of the gas to beburned.

10. A steam aspirating gas flare for smokeless burning with less noiseof undesired gas comprising,

a. specific gravity analyzer means for determining the specific gravityof the gas to be burned,

b. steam flow controller means for controlling the steam-to-gas mixturesupplied to the flare, and

c. said steam flow controller means being responsive to said specificgravity analyzer means for varying the steam relative to the specificgravity of the gas to be burned for providing a smokeless air-to-gasburning mixture in the flare with less steam usage and reduced noise.

11. A flare as recited in claim 10 wherein,

a. said specific gravity analyzer means comprises means forcontinuouslyanalyzing the gas prior to being supplied to the flare for burning.

12. A flare as recited in claim 10 wherein the gas is supplied to theflare through a main line and wherein,

a. said specific gravity analyzer means comprises a specific gravityanalyzer connected to the main line for continuously circulating the gasfrom the main line, through the specific gravity analyzer, and back tothe main line for continuous analyzing of the gas prior to being burnedin the flare.

13. A flare as recited in claim 10 including further,

a. ratio varying means for varying the steam-to-gas mixture output ofsaid steam flow controller, and

b. said ratio varying means being responsive to said gas specificgravity analyzer means for controlling said steam flow controller meansfor controlling the steam-to-gas mixture relative to the specificgravity of the gas being burned.

14. A flare ,as recited in claim 10 wherein,

a. said steam flow controller means has a first output steam-to-gasmixture ratio relative to the amount of gas flow to the flare, and

b. said steam flow controller means is responsive to said specificgravity analyzer means for varying said first output by varying thesteam relative to the specific gravity'of the gas to be burned.

15. A flare as recited in claim 10 wherein,

a. said steam flow controller means has a first steam output relative tothe. amount of gas flow to the flare, and v b. said steam flowcontroller means is responsive to said specific gravity analyzer meansfor further varying said first output'relative to the specific gravityof the gas to be burned. v

16. A flare as recited claim 15 wherein,

a. said steam flow'controller means is responsive to said specificgravity analyzer means for varying said first output in proportion tothe specific gravity of the gas to be burned.

17. A flare as recited in claim 15 wherein,

a. said steam flow controller means is responsive to said specificgravity analyzer means for varying said first output in directproportion to the specific gravity of the gas to be burned. 18. A flareas recited in claim 15 wherein, a. said flare has steam multipliermeans, and b. said steam flow controller means is responsive to saidsteam multiplier means for multiplying the steamfirst output by a factorrelative to the specific gravity of the gas to be burned. 19. A steamaspirating gas flare for burning undesired gas having a steam flowcontroller comprising,

a. a main gas line connected to the flare, b. a specific gravityanalyzer connected to said main gas line having an output, 0. a gas flowdetector connected between said main gas lineand a steam flow controllerhaving an outthe undesired gas with less steam usage and reduced noise.

20. A flare as recited in claim 19 wherein,

a. said variable ratio controller multiplies said gas flow detectoroutput by the specific gravity analyzer output for ensuring smokelessburning of the undesired gas with less noise.

1. A method for smokelessly burning gas with less noise in a steamaspirating flare having means for controlling the amount of steam to theflare for controlling the amount of air drawn in for mixing with the gasfor burning, comprising the steps of, a. determining the specificgravity of the gas being burned, and b. varying the amount of steam tothe flare relative to the specific gravity of the gas to be burned forproviding a smokeless air-to-gas burning mixture in the flare with lesssteam usage and reduced noise.
 2. A method as recited in claim 1including the additional steps of, a. varying the amount of steamrelative to the amount of gas flowing to the flare, and b. varying thefirst amount of steam to a second amount of steam relative to thespecific gravity of the gas to be burned for providing a smokelessair-to-gas burning mixture in the flare with less steam usage andreduced noise.
 3. A method as recited in claim 1 wherein the second stepcomprises further, a. determining the amount of steam required tomaintain a desired steam-to-gas ratio for the flare for the particularamount of gas flow, and b. multiplying the amount of steam supplied by afactor relative to the specific gravity of the gas for providing thesmokeless air-to-gas burning mixture in the flare with less noise.
 4. Amethod as recited in claim 1 wherein the second step comprises further,a. determining the amount of steam required to maintain a desiredsteam-to-gas ratio for the flare gas flow, and b. varying thesteam-to-gas ratio relatively to the specific gravity of the gas forproviding a smokeless air-to-gas burning mixture in the flare with lessnoise.
 5. A method for smokelessly burning gas with less noise in a highpressure gas aspirating flare having means for controlling the amount ofhigh pressure gas to the aspirating flare for controlling the amount ofair drawn in for mixing with the gas to be burned, comprising the stepsof, a. determining the specific gravity of the gas to be burned, and b.varying the amount of high pressure aspirating gas to the flare relativeto the specific gravity of the gas to be burned for providing asmokeless air-to-gas burning mixture in the flare with less highpressure gas usage and reduced noise.
 6. A method for smokelesslyburning gas with less noise in a steam aspirating flare having means forcontrolling the steam-to-gas ratio in the flare comprising the steps of,a. determining a first steam-to-gas ratio relative to the amount of gasflow to the flare, b. determining the specific gravity of the gas to beBurned, and c. varying the first steam-to-gas ratio relative to thespecific gravity of the gas to provide a smokeless air-to-gas burningmixture in the flare with less steam usage and reduced noise.
 7. Amethod as recited in claim 6 wherein the last step comprises further, a.varying the amount of steam in the steam-to-gas ratio in relation to thespecific gravity of the gas to be burned.
 8. A method as recited inclaim 6 wherein the last step comprises further, a. varying the amountof steam in the steam-to-gas ratio in proportion to the specific gravityof the gas to be burned.
 9. A method as recited in claim 6 wherein thelast step comprises further, a. varying the amount of steam in thesteam-to-gas ratio in substantially direct proportion to the specificgravity of the gas to be burned.
 10. A steam aspirating gas flare forsmokeless burning with less noise of undesired gas comprising, a.specific gravity analyzer means for determining the specific gravity ofthe gas to be burned, b. steam flow controller means for controlling thesteam-to-gas mixture supplied to the flare, and c. said steam flowcontroller means being responsive to said specific gravity analyzermeans for varying the steam relative to the specific gravity of the gasto be burned for providing a smokeless air-to-gas burning mixture in theflare with less steam usage and reduced noise.
 11. A flare as recited inclaim 10 wherein, a. said specific gravity analyzer means comprisesmeans for continuously analyzing the gas prior to being supplied to theflare for burning.
 12. A flare as recited in claim 10 wherein the gas issupplied to the flare through a main line and wherein, a. said specificgravity analyzer means comprises a specific gravity analyzer connectedto the main line for continuously circulating the gas from the mainline, through the specific gravity analyzer, and back to the main linefor continuous analyzing of the gas prior to being burned in the flare.13. A flare as recited in claim 10 including further, a. ratio varyingmeans for varying the steam-to-gas mixture output of said steam flowcontroller, and b. said ratio varying means being responsive to said gasspecific gravity analyzer means for controlling said steam flowcontroller means for controlling the steam-to-gas mixture relative tothe specific gravity of the gas being burned.
 14. A flare as recited inclaim 10 wherein, a. said steam flow controller means has a first outputsteam-to-gas mixture ratio relative to the amount of gas flow to theflare, and b. said steam flow controller means is responsive to saidspecific gravity analyzer means for varying said first output by varyingthe steam relative to the specific gravity of the gas to be burned. 15.A flare as recited in claim 10 wherein, a. said steam flow controllermeans has a first steam output relative to the amount of gas flow to theflare, and b. said steam flow controller means is responsive to saidspecific gravity analyzer means for further varying said first outputrelative to the specific gravity of the gas to be burned.
 16. A flare asrecited in claim 15 wherein, a. said steam flow controller means isresponsive to said specific gravity analyzer means for varying saidfirst output in proportion to the specific gravity of the gas to beburned.
 17. A flare as recited in claim 15 wherein, a. said steam flowcontroller means is responsive to said specific gravity analyzer meansfor varying said first output in direct proportion to the specificgravity of the gas to be burned.
 18. A flare as recited in claim 15wherein, a. said flare has steam multiplier means, and b. said steamflow controller means is responsive to said steam multiplier means formultiplying the steam first output by a factor relative to the specificgravity of the gas to be burned.
 19. A steam aspirating gas flare forburning undeSired gas having a steam flow controller comprising, a. amain gas line connected to the flare, b. a specific gravity analyzerconnected to said main gas line having an output, c. a gas flow detectorconnected between said main gas line and a steam flow controller havingan output signal for controlling the steam flow relative to the gasflow, d. a variable ratio controller connected between said gas flowdetector and the steam flow controller, and e. said variable ratiocontroller being responsive to said specific gravity analyzer output formodifying said gas flow detector control signal to said steam flowcontroller for ensuring smokeless burning of the undesired gas with lesssteam usage and reduced noise.
 20. A flare as recited in claim 19wherein, a. said variable ratio controller multiplies said gas flowdetector output by the specific gravity analyzer output for ensuringsmokeless burning of the undesired gas with less noise.